CHILTERN trains from Banbury, Bicester, and Haddenham & Thame Parkway will be running into London Marylebone today.
The station had been closed since the weekend following a fire that took out some of its signals.
However, Chiltern Railways has confirmed this morning Marylebone is open and services are running.
There may be some delays or cancellations at short notice though because the disruption has meant not all the company's trains are where they should be along its network.
A spokesman said this morning: "Network Rail engineers have been working around the clock so that we can operate services in and out of the station.
"We are now running a normal service however, there may be some minor delays and last minute cancellations as trains will be out of place. Some trains may also be formed of fewer carriages."
Because services have resumed, Chiltern says passengers cannot use its tickets with other companies.
Chiltern had hoped Marylebone would be open yesterday afternoon but the fire, which destroyed a two-metre section of cable, had caused more damage than initially thought.